MODELING AND SIMULATING THE EVOLUTION OF RESISTANCE AGAINST ANTIBIOTICS

An epidemiological model is proposed for the spread of resistance agai nst antibiotics in populations of bacterial pathogens. The host popula tion, which is assumed to be constant, is divided into three compartme nts, viz. susceptible, hosts infected by an antibiotic-sensitive strai n and hosts infected by a resistant strain. It is further assumed that susceptibles can be infected by either strain and that there is a pos sibility for cross-infection between hosts infected by the two strains . The rate of cross-infection can be enhanced by mutations or the tran sfer of plasmids conferring resistance. Equilibrium analysis was perfo rmed in order to determine which of the strain 'wins' the competition by the host. It is assumed that the eventual shift in the competition between the two strains is due to treatment by antibiotic (selective p ressure).